Fuel injector rack setting means



A. G. JORDAN FUEL. INJEGTOR RACK SETTING MEANS April zo, 1.965

Filed June 15, 1962 AES \\\\\\\\\\\\`\\\\MMXv 1 N VEN TOR. 4l ,fo/vso 6.Joemn/ H/s Arron/EY United States Patent() 3,179,053 FUEL INJECTOR RACKSETTING MEANS Alfonso G. Jordan, 879 Walnut St., San Jose, Calif. FiledJune 15, 1962, Ser. No. 202,780

8 Claims. (Cl. 1013-37) This invention relates to fuel injectors of thetype employed in multi-cylindered diesel engines and more particularlyto an improved injector rack setting means therefor.

The present invention is more particularly directed to an injector racksetting means for unit injectors of the type used in General Motorsdiesels and the like. The demand for more power and greater economy ofoperation and maintenance in diesel engines makes it most critical thatfuel distribution to all cylinders be made as equal as possible.

In the General Motors two-cycle diesel engines, equal distribution offuel injected per stroke of each injector is set by means of its rackand gear after the injectors are installed in the cylinder heads of theengine. Each rack -is set at a pre-determined iixed measurement. Forexample, in the injectors utilized primarily in the railroad industry,the rack is set one inch from the end of the rack tothe 'body of theinjector with no way to compensate for unequal delivery due to wear ofthe plunger and/ or spray tip -assembly of the injector.

The present method of equalizing fuel delivery for a particular set ofinjectors to be used in an engine is accomplished by running each suchinjector in a bench type test stand to determine its output. Forexample, on the General Motors Model 567C, Needle Injector at one inchrack setting `as explained above, 800 rpm. and 800 strokes pm., the`accepted delivery tolerance is from 424 to 440 ccs. In other word-s ifall 16 injectors are within that range they are assumed to he Ias closeto equal as is feasibly possible. This allows a latitude of a maximum of16 ccs. differential between the least and greatest fuel delivery of aset of injectors.Y

If an injector is tes-ted and found to deliver say 4 20 ccs., thepresent method of correcting this to get it'into the desired range is todisassemble the injector and install a new plunger and bushing and/or anOld Tip Assembly with the holes worn sufliciently as not to allow toomuch back pressure so that more fuel will ow through at a given stroke.In other cases it may be necessary to install a new type gear that willadvance the plunger helix a suicient amount relative to the one inchsetting of the rack to increase the output of a particular injector tothe 4244140 oc. accepted range. Aside from the fact that some injectors-will by chance fall into the accepted range, all others according tothese methodswill require that the injector be disassembled and theparts replaced `and retested with the possibility that this operationwill have to be repeated. There is stilla great deal of guesswork andVery little control over the4 increase or decrease of injector output.The prime expense of this method is an increase in inventory of injectorparts, anfincrease of Vconsumption of injector parts and additionallabor and usage of the injector test stand. i j

It is an object of the presentinvention to alleviate the need forsuchextensive and time consuming changes and tests in order to equalize thefuel distribution of a par-v ticular set of injectors. In accordancewith the present invention under the sameconditions, assuming the`injector was set'with one inch rack setting at 80() r.p.m.s 'and 800strokes with a delivery of 420 cos., it is contemplated that theappropriate adjustment of fuel flow Within one cc.`of delivery can bemade without `disassembling the injector or retesting the injector.

`It is another object of this invention to provide a means 3,179,053Patented Apr. 20, 1965 ice for varying the length of the rack to varythe port adjustment of the fuel intake to thereby increase and/ordecrease the amount of fuel injected per stroke.

It is yet another object to provide a rack stroke adjusting meansaccessible to mechanics whereby compensation for fuel injectiondifferences between injectors can he accomplished on the test stand.

These and other objects and advantages of the present invention willbecome apparent from a reading of the following description in the lightof :the drawings in which:

FIG. l is a detailed section (partially in elevation) of a GeneralMotors diesel fuel injector with linkage for operating the same.

FIG. 2 is a fragmentary portion of FIG. 1 with p-arts thereof in adiiferent position.

FIG. 3 is an enlarged longitudinal section of the right hand end of therack bar of FIGS. 1 and 2.

FIG. 4 is an elevational view of FIG. 3 as seen from above therein. Y

FIG. 5 is an end elevation and partial section of FIG. 3 takensubstantially along line 5 5 thereof.

The injector 1) shown in FIG. 1 consists of a forged steel, hollow body11 in which is housed a high pressure pump 12 by which a measuredquantity of fuel is forced intoand through a `spray nozzle 13 fordischarge into the cylinder of a diesel engine (not shown);

Tihe pump 12 consistsof a bushing 14 so disposed in the hollow body 11as to provide a somewhat cylindrical clearance space 15 between thebushing 14 and inner Wall of the housing 11 to allow fuel oil tosurround the bushing.

The housing 11 has an inlet passage 16 communicating with thecylindrical space 15 and with a fuel supply line or conduit 17 in amanner well known in the art.

A plunger 18 is arranged in an axial bore 19 in the bushing 14 forreciprocation therein by means of a spring loaded plunger follower 20which extends upwardly exteriorly of the A'body 11 for operation by oneend 21 of a rocker arm (not shown) synchronized with stroke of thecylinder of the diesel `engine on which the injector `1() is installed.

As best seen in FIGS. 1 and 2 the bushing 14 has upper and lower ports22 and 23 formed therein between the cylindrical space 15 and the pumpbore 19 to admit fuel oil into the latter. The fuel oil is constantlypresent inthe space 1S and under suicient pressure to supply the demandlof the pump 12, limited only by the stroke of the plunger 18 and ahelical chamber or recess 25 formed on the plunger for periodiccommunication with the upper and lower ports 22 and 23.

Periodic communication of the helical recess 25 with the fuel admittanceports 22-23 is controlled by relative turning of therentire plunger 18within the pump bore 19. The means for turning the plunger 18 includes apinion gear 26 slid-ably -arranged -on the upper end of the plunger 18in an area of confinement Within the housing 11, the

plunger and pinion gear having related flat surfaces, one i of which isshown at 27 in FIG. 2 to assure turning of the plunger as it isreciprocated within the pump bore 19 of `the bushing 14. j

A rack'bar 30 is arranged upon the housing 11 for reciprocation throughthe same tangentially of the pinion gear 26 so that the teeth 31 on therack bar mesh with the gear 26 to tur-n the latter in accordance withthe later-al strokes of the rack `bar 30.`

. The present'invention resides `in means 35 for lengthening and/orshortening the rack bar 30 for changing Vthe relative disposition of thehelical chamber 25 on the plunger 18 .relative to the upper and lowerports 22 and 23 respectively. j i

The means (FIGS. 3, 4 and 5) includes a movable drive end 36 for therack 30 having the conventional roller 3:'7y kmounted on a pin 33 whichis sweat onto the end 36. The main body 32 of the rack 3i) is drilledand tapped axially thereof as at 33 for receiving one end of a selflocking screw shank 39 of an adjusting bolt 40. This bolt t0 vhas aheaded end 41 disposed in an enlarged bore 42 in the drive end 36 of therack, the screw shank 39 extending through a minor bore i3 for threadedconnection in the tapped bore 33 of the main body 32 of the rack 30. Asbest seen in FIGS.v 3 and 4 the roller Carrying pin 3S extendsdiametrically across the bore 42 and has a transverse bore 44 formedtherethrough in axial alignment with the rack 30 `and its drive end 36.This provides an access opening from the open end 45 of the bore 42 tothe head 4l of the adjusting bolt 4t). This access opening is necessaryfor a hex-wrench W adapted to fit the hex-socket 46 in the head 4f. ofbolt 40. The wrench is the well known Allen head Wrench W and bolt nowso widely used. j

Y The head 41 of the bolt et) is disposed between the pin 33 and theshoulder 47 provided at the junction ofthe minor and major bores 43 and42. A neoprene washer 48 is disposed between the head 4I of bolt 40 andthe shoulder 47 to maintain the head 4l against the pin 38 and toprevent back lash when the head 4I is turned relativeto the metalsurface at the shoulder 47.

The shank 39 ofthe bolt 4i) is of alloyed steel to likewise preventgalling of the metals when the bolt is turned to draw its head 4l andthe drive end 36 of the rack toward the main, body 32 thereof. The shank39 of the bolt it? has a Nylock insert 49 (FIG. 3) which expands againstthe inside threading in the main body 32 of the rack 39 to frictionallyhold the screw shank in any adjusted position relative thereto. Uponturning of the screw bolt 40 by means of the Allen head wrench W themovable drive end 36 is moved toward and/ or from the main 'body 32 ofthe rack 30 to change the relative position of the helical chamber 25relative to the pump ports 22 and 23.

This means 5I comprises a pair of spring steel expansion pins 52 and 53arranged in aligned bores in the main bodyl 31'and the drive end 36 ofthe rack 30. The bores 54 and 55 in the-main body 31 are diametricallyopposite each other as are the bores 54' and 55 in the drive end 36. Asbest seen in FIG. 5, the pins 52 and 53 are identically Cshaped inYcross section and being precision made of spring steel tend to assume aslightly greater diameter than the bores into which they are to fit.

These pins are seated firmly in the bores 54 and 55 in they main body 31and extend beyond the outer end thereof a length substantiallycomparable to `that of Athe drive end 36 ofthe rack. The pins 52 and 5,3serve to guide and support the drive end 36 in alignment with the mainbody 31 and to maintain theroller y357 in correct position yforoperation by itsoperating 1everv5t). The lever 5@ rocks to and fro intimed relation with the engine in the usual manner to load the'pump withfuel once in each cycle of the engine.

Referring toFIG. l it will be noted that when the plunger 18 is all theWay up (withdrawn) relative to the bore "19 of the pump bushing I4. fuel,is admittedk into the bore i9 below the plunger via the lower port 23.

The plunger IS has a relief -port 56 formed axially thereof from itslower end to a T head cross port 57 which opens up into the recesschamber 25. By this arrangement when the plunger moves downwardly tocompress the full charge of fuel oil below it, any excess fuel will jsurge up through relief port 56 and into the helical recess `or chamber25. This will occur as long as the chamber 25 is in communicaion witheither the vupper and/or the d lower ports 2243. However, once theseports 22 and 23 are cut off from the chamber 25, the charge of fuel oilbeneath the plunger is compressed sufficiently to overcome a springloaded check valve 60 (dotted lines FIG. l) so that the charge of fuelwill be squirted out the nozzle end 13 of the injector body. It willthus be appreciated that the position of the Arecess chamber 25 relativeto the ports 22-23 as determined by the'stroke of the rack 34B is verycritical,

By the arrangement of this invention the rack 30 can be set at anydesired vposition of adjustment to Yprolong or shorten the .period ofcommunication of the helical chamber 25 with the fuel intake phase ofthe operation of the injector and thereby increase or decrease theamount `of fuel injected per stroke. In other words, turning of thescrew bolt 40 to lengthen the rack 30 will increase the output of fueland by tightening the screw into the tapped bore 33 the output of fuelwill be decreased.

With the rack adjusting feature of the present invention the severalinjectors on an engine can all be calibrated to any-output of fuelwithin one cc. Moreover, this can be done 'on the test stand,` ie., withassurance that the injector will admit fuel well Within the allowedlimits. In this manner, injectors which might otherwise be discardedwill be saved and the life of injectors can be prolonged with assuranceof uniform, i.e., equalized fuel injectors on all cylinders.

While I have described my Yinvention in specific detail it will beappreciated by those skilled in the art that the same may be susceptibleto variations, alterations and/ or modifications Without departing fromthe spirit of my invention. I therefore Vdesire to avail myself of allvariations, alterations and/or modifications of structure which mayreasonably come within the purview of the following claims. Y

What I claim -as new and desire to protectby Letters Patent is:

l. In a fuel injector including a pump in which a pump plungerreciprocable within the injector body has a helical recess communicablewith xed fuel inlet ports in the injector body, Iand yan injector rackhaving itstoothed main body meshing with a pinion gear on said plungerand its drive end engaged by a rocker arm for moving said rack axiallyto and froto turn the plunger while the latter reciprocates formaintaining said lhelical recess in communication With at least one ofthe fixed ports for a period of time sufficient to load said pump with apredetermined quantity of fuel; an injector rack setting meanscomprising a separate drive end on said body having a rocker armengaging roller Von one side thereof, la pin on said roller projectingdiametrically through' the drive end of said rack, said'drive Vendhaving a major bore and a minor bore the latter facing said main body ofthe rack and in axial alignment therewith, a screw shank extendingthrough said minor bore, said screw shank having a head portion withinsaid major bore and engaging said pin, a tapped axial bore in the mainbody of saidV -same to lengthen and shorten the rack to thereby changethe period of communication of'said recess with one or Vboth ofsaidports; n

2. I n a fuel injector including a pump in which a pump *plungerreciprocable within the injector body has a helical recess communicablewith fixed fuel inlet ports in the injector body, and an injector rackhaving its toothed main body meshing with a piniongear on said plunger'and its drive end engaged by a rocker arm for moving said racky.axially to and fro to turn"the plunger during its reciprocation formaintaining said helical recess in communication with at least `one-lofthe fixed ports for a periodofwtime suiiicient -to load, said pump withapredetermined quantity of fuel; an injector rack setting meanscomprising :a separate driveend on said body having a rocker armengaging roller on one side thereof, a pin on said roller projectingdiametrically through the drive end of said rack, said drive end havinga major bore and a minor bore the latter facing said main body of therack and in axial alignment therewith, a screw shank extending throughsaid minor bore, said screw shank having a head portion within saidmajor bore and engaging said pin, a tapped axial bore in the main bodyof said rack for receiving the threaded end of saidV screw shank, anaccess bore diametrically through said pin in axial alignment with saidmajor bore facilitating admittance of a tool to the head of said screwshank for turning the same to lengthen and shorten the rack totherebychange the period of communication of said recess with one orboth of said ports, and means offset radially from the screw shank insaid main body of said rack and extending into said drive end thereoffor resisting turning of the latter relative to said main body duringturning of said screw to thereby maintain said roller in correctposition to engage said rocker arm.

3. In a fuel injector including a pump in which a pump plungerreciprocable within'the injector body has a helical recess communicablewith fixed fuel inlet ports in the injector body, and an injector rackhaving its toothed main body meshing with a pinion gear on said plungerand its drive end engaged by a rocker arm for moving said rack axiallyto and fro to Iturn the plunger as the plunger reciprocates formaintaining said helical recess in communication with :at least one ofthe fixed ports for a period of time sufficient to load said pump with apredetermined quantity of fuel; an injector rack setting meanscomprising a separate drive end on said body having a rocker armengaging roller on one side thereof, a pin on said roller projectingdiametrically through the drive end of said rack, said drive end havinga major bore and a minor bore the latter facing said main body of therack and in axial alignment therewith, a screw shank extending throughsaid minor bore, said screw shank having a head portion within saidmajor bore and engaging said pin, a tapped .axial bore in the main bodyof said rack for receiving the threaded end of said screw shank, anaccess bore diametrically through said pin in axial alignment with saidmajor bore facilitating admittance of a tool to the head of said screwshank for turning the same to lengthen and shorten the rack to therebychange the period of communication of said recess with one or both ofsaid ports, said main body and said drive end thereof havingdiametrically opposed .aligned bores extending parallel to the axis ofsaid screw shank, and an expansion pin extending into each set of saiddiametrically opposed bores for maintaining said main body and drivebody againstV relative rotation during turning of said screw shank andfor guiding said drive end of said rack during movement thereof towardand from said main body during turning of said screw shank.

4. In combination with an injector rack having a toothed portion meshedwith pinion gear on a fuel pump the plunger of which has an helicalrecess communicable with fuel inlet ports for admitting a pre-determinedquantity of fuel to said pump; .an injector rack setting meanscomprising a separate drive end on the toothed portion of said rackhaving a rocker arm engaging roller on one side thereof, a pin on saidroller projecting diametrically through the drive end of said rack, saiddrive end having a minor bore at one end facing the toothed portion ofsaid rack and in axial alignment therewith, said drive end having amajor bore at its opposite end providing a shoulder at the juncture ofsaid minor bore, a headed screw having its shank extending through saidminor bore and itsV head portion within said major bore between saidshoulder and said pin, a tapped axial bore in the toothed portion ofsaid rack for receiving the threaded end of said screw shank, and anaccess bore diametrically through said pin in axial alignment with saidmajor bore facilitating admittance of a tool to the head of said screwshank for turning the same to lengthen and shorten the rackand therebychange the position of the helical recess on said plunger relative tosaid ports.

5. In combination with an injector rack having a toothed portion meshedwith pinion gear on a fuel pump the plunger of which has an helicalrecess communicable with fuel inlet ports for admitting a predeterminedquantity of fuel to said pump; an injectorrack setting means comprisinga separate drive end on the-toothed portion of said rack having a rockerarm engaging roller on one side thereof,4 a pin on said rollerprojecting diametrically through the drive end of said rack, said driveend having a minor bore at one end facing the toothed portion of saidrack and in axial alignment, therewith, said drive end having a majorbore at its opposite end providing a shoulder at the juncture of saidminor bore, a headed screw having its shank extending through said minorbore and its head portion within said major bore between said shoulderand said pin, a tapped axial bore in the toothed portion of said rackfor receiving the threaded end of said screw shank, an access borediametrically through said pin in axial alignmentwith said major borefacilitating admittance of a tool to the head of said screw shank `forturning the same to lengthen and -shorten the rack and thereby changethe position of the helical recess on said plunger relative to saidports, said toothed portion and said drive end of said rack havingdiametrically opposed aligned bores extending parallel to the axis ofsaid screw shank, and an expansion pin extending into each set of saiddiametrically opposed bores for resisting relative turning of thetoothed portion and the drive end of said rack during turning of saidscrew shank and for guiding said drive endA of said rack during movementthereof toward and from said toothed portion during turning of saidscrew shank.

6. In an injector rack having a main rack body provided with a toothedportion engaging a pinion gear slidable on the plunger of a pump forturning said plunger to position an helical recess thereon incommunication with fuel ports for a predetermined time during eachstroke of such plunger, a rack setting means comprising a separate driveend on said main body having a rocker arm engaging roller on one sidethereof, a pin on said roller projecting diametrically through saiddrive end, said drive end having an axial minor bore at one end and amajor bore at its opposite end providing a shoulder within said driveend, a screw shank extending through said minor bore, said screw shankhaving a head portion within said major bore engaging said shoulder andsaid pin for moving the drive end with said screw shank, a tapped axialbore in said main body for receiving the threaded end of said screwshank, and an access bore diametrically through said pin in axialalignment with said major bore Ifacilitating admittance of a tool to thehead of said screw shank to turn the same to lengthen and shorten therack for prolonging and diminishing the time of communication of thehelical recess on said plunger with the fuel ports during each stroke ofsaid plunger.

.7. In an injector rack having a main rack body provided with a toothedportion engaging a pinion gear slidable on the plunger of a pump forturning said plunger to position an helical recess thereon incommunication with fuel ports for a predetermined time during eachstroke of such plunger, a rack setting means comprising a separate driveend on said main body having a rocker arm engaging roller on one sidethereof, a pin on said roller projecting diametrically through saiddrive end, said drive end having an axial minor bore at one end with amajor bore at its opposite end providing a shoulder within said driveend, a screw shank extending through said minor bore, said screw shankhaving a head portion within said major bore engaging saidshoulreceiving the threaded end of said screwshank, an ac- Y cess borediametrically through said pin in axial align ment with said major borefacilitating admittance of a tool to the head of said screw shank toturn the same to lengthen and shorten the rack for prolonging anddiminishing the time of communication of the helical recess on saidplunger with the yfuel ports during each stroke of said plunger, andmeans for guiding vsaid drive lend for non-turning movement toward andfrom said main body during turning of said screw.-

8. In an injector rack 'having a main rack body provided with a toothedportion engaging a pinion gear slidable fon the plunger of a pump forturning said plunger to position an helical recess thereon incommunication with fuel ports for a predetermined time during eachstroke of such plunger, a rack setting means comprising a separate driveend on said'main body having a rocker arm engaging roller on one sidethereof, apin on said roller projecting diametrically through said driveend, said drive end having an axial minor bore at one end and a majorbore at its opposite end providing a shoulder within said drive end, ascrew shank extending through said minor bore, said screw shank having ahead portion within said major bore engaging said shoulder and said pinfor moving the drive end with said screw shank, a tapped axialy bore insaid main body for receiving the threaded end of said screw shank, anaccess bore diametrically through said pin in axial alignment with saidmajor bore facilitating admittance of a tool to the head of said screwYshank to turn the same to lengthen and shorten the rack for prolongingyand diminishing the time of communication of the helical recess on saidplunger with the fuel ports during each stroke of said plunger, meansfor guiding said drive end for non-turning movement toward and from saidmain body during turning of said screw Vcomprising diametrically opposedaligned bores in said main body and said drive end extending parallel tothe axis of said screw shank, and an expansion pin extending in'each ofsaid diametrically opposed bores in said-main body and into thediametrically opposed bores in said drive end for frictionally slidingmovement relative thereto as said drive end moves toward and from themain body of said rack during turning of said screw shank.

References Cited by the Examiner UNITED 'STATES PATENTS 1,520,401 k12/24Brady 287-61 1,593,582 7/26 Leo 287-62 X 2,317,022 4/43 Benjamin 123-l40y2,555,124 5/51 Gothberg `287--59 2,635,590 4/53 Simon 103-41 LAURENCEV. EFNER, Primary Examiner.

1. IN A FUEL INJECTOR INCLUDING A PUMP IN WHICH A PUMP PLUNGERRECIPROCABLE WITHIN THE INJECTOR BODY HAS A HELICAL RECESS COMMUNICABLEWITH FIXED FUEL INLET PORTS IN THE INJECTOR BODY, AND AN INJECTOR RACKHAVING ITS TOOTHED MAIN BODY MESHING WITH A PINION GEAR ON SAID PLUNGERAND ITS DRIVE END ENGAGED BY A ROCKER ARM FOR MOVING SAID RACK AXIALLYTO AND FRO TO TURN THE PLUNGER WHILE THE LATTER RECIPROCATES FORMAINTAINING SAID HELICAL RECESS IN COMMUNCATION WITH AT LEAST ONE OF THEFIXED PORTS FOR A PERIOD OF TIME SUFFICIENT TO LOAD SAID PUMP WITH APREDETERMINED QUANTITY OF FUEL; AN INJECTOR RACK SETTING MEANSCOMPRISING A SEPARATE DRIVE END ON SAID BODY HAVING A ROCKER ARMENGAGING ROLLER ON ONE SIDE THEREOF, A PIN ON SAID ROLLER PROJECTINGDIAMETRICALLY THROUGH THE DRIVE END OF SAID RACK, SAID DRIVE END HAVINGA MAJOR BORE AND A MINOR BORE THE LATTER FACING SAID MAIN BODY OF THERACK AND IN AXIAL ALIGNMENT THEREWITH, A SCREW SHANK EXTENDING THROUGHSAID MINOR BORE, SAID SCREW SHANK HAVING A HEAD PORTION WITHIN SAIDMAJOR BORE AND ENGAGING SAID PIN, A TAPPED AXIAL BORE IN THE MAIN BODYOF SAID RACK FOR RECEIVING THE THREADED END OF SAID SCREW SHANK, AND ANACCESS BORE DIAMETRICALLY THROUGH SAID PIN IN AXIAL ALIGNMENT WITH SAIDMAJOR BORE FACILITATING ADMITTANCE OF A TOOL TO THE HEAD OF SAID SCREWSHANK FOR TURNING THE SAME TO LENGTHEN AND SHORTEN THE RACK TO THEREBYCHANGE THE PERIOD OF COMMUNICATION OF SAID RECESS WITH ONE OR BOTH OFSAID PORTS.